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-rw-r--r--src/basic/io-util.c345
1 files changed, 345 insertions, 0 deletions
diff --git a/src/basic/io-util.c b/src/basic/io-util.c
new file mode 100644
index 0000000..7bb9e15
--- /dev/null
+++ b/src/basic/io-util.c
@@ -0,0 +1,345 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <limits.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include "io-util.h"
+#include "string-util.h"
+#include "time-util.h"
+
+int flush_fd(int fd) {
+ int count = 0;
+
+ /* Read from the specified file descriptor, until POLLIN is not set anymore, throwing away everything
+ * read. Note that some file descriptors (notable IP sockets) will trigger POLLIN even when no data can be read
+ * (due to IP packet checksum mismatches), hence this function is only safe to be non-blocking if the fd used
+ * was set to non-blocking too. */
+
+ for (;;) {
+ char buf[LINE_MAX];
+ ssize_t l;
+ int r;
+
+ r = fd_wait_for_event(fd, POLLIN, 0);
+ if (r < 0) {
+ if (r == -EINTR)
+ continue;
+
+ return r;
+ }
+ if (r == 0)
+ return count;
+
+ l = read(fd, buf, sizeof(buf));
+ if (l < 0) {
+ if (errno == EINTR)
+ continue;
+
+ if (errno == EAGAIN)
+ return count;
+
+ return -errno;
+ } else if (l == 0)
+ return count;
+
+ count += (int) l;
+ }
+}
+
+ssize_t loop_read(int fd, void *buf, size_t nbytes, bool do_poll) {
+ uint8_t *p = ASSERT_PTR(buf);
+ ssize_t n = 0;
+
+ assert(fd >= 0);
+
+ /* If called with nbytes == 0, let's call read() at least once, to validate the operation */
+
+ if (nbytes > (size_t) SSIZE_MAX)
+ return -EINVAL;
+
+ do {
+ ssize_t k;
+
+ k = read(fd, p, nbytes);
+ if (k < 0) {
+ if (errno == EINTR)
+ continue;
+
+ if (errno == EAGAIN && do_poll) {
+
+ /* We knowingly ignore any return value here,
+ * and expect that any error/EOF is reported
+ * via read() */
+
+ (void) fd_wait_for_event(fd, POLLIN, USEC_INFINITY);
+ continue;
+ }
+
+ return n > 0 ? n : -errno;
+ }
+
+ if (k == 0)
+ return n;
+
+ assert((size_t) k <= nbytes);
+
+ p += k;
+ nbytes -= k;
+ n += k;
+ } while (nbytes > 0);
+
+ return n;
+}
+
+int loop_read_exact(int fd, void *buf, size_t nbytes, bool do_poll) {
+ ssize_t n;
+
+ n = loop_read(fd, buf, nbytes, do_poll);
+ if (n < 0)
+ return (int) n;
+ if ((size_t) n != nbytes)
+ return -EIO;
+
+ return 0;
+}
+
+int loop_write(int fd, const void *buf, size_t nbytes, bool do_poll) {
+ const uint8_t *p = ASSERT_PTR(buf);
+
+ assert(fd >= 0);
+
+ if (_unlikely_(nbytes > (size_t) SSIZE_MAX))
+ return -EINVAL;
+
+ do {
+ ssize_t k;
+
+ k = write(fd, p, nbytes);
+ if (k < 0) {
+ if (errno == EINTR)
+ continue;
+
+ if (errno == EAGAIN && do_poll) {
+ /* We knowingly ignore any return value here,
+ * and expect that any error/EOF is reported
+ * via write() */
+
+ (void) fd_wait_for_event(fd, POLLOUT, USEC_INFINITY);
+ continue;
+ }
+
+ return -errno;
+ }
+
+ if (_unlikely_(nbytes > 0 && k == 0)) /* Can't really happen */
+ return -EIO;
+
+ assert((size_t) k <= nbytes);
+
+ p += k;
+ nbytes -= k;
+ } while (nbytes > 0);
+
+ return 0;
+}
+
+int pipe_eof(int fd) {
+ int r;
+
+ r = fd_wait_for_event(fd, POLLIN, 0);
+ if (r <= 0)
+ return r;
+
+ return !!(r & POLLHUP);
+}
+
+int ppoll_usec(struct pollfd *fds, size_t nfds, usec_t timeout) {
+ int r;
+
+ assert(fds || nfds == 0);
+
+ if (nfds == 0)
+ return 0;
+
+ r = ppoll(fds, nfds, timeout == USEC_INFINITY ? NULL : TIMESPEC_STORE(timeout), NULL);
+ if (r < 0)
+ return -errno;
+ if (r == 0)
+ return 0;
+
+ for (size_t i = 0, n = r; i < nfds && n > 0; i++) {
+ if (fds[i].revents == 0)
+ continue;
+ if (fds[i].revents & POLLNVAL)
+ return -EBADF;
+ n--;
+ }
+
+ return r;
+}
+
+int fd_wait_for_event(int fd, int event, usec_t timeout) {
+ struct pollfd pollfd = {
+ .fd = fd,
+ .events = event,
+ };
+ int r;
+
+ r = ppoll_usec(&pollfd, 1, timeout);
+ if (r <= 0)
+ return r;
+
+ return pollfd.revents;
+}
+
+static size_t nul_length(const uint8_t *p, size_t sz) {
+ size_t n = 0;
+
+ while (sz > 0) {
+ if (*p != 0)
+ break;
+
+ n++;
+ p++;
+ sz--;
+ }
+
+ return n;
+}
+
+ssize_t sparse_write(int fd, const void *p, size_t sz, size_t run_length) {
+ const uint8_t *q, *w, *e;
+ ssize_t l;
+
+ q = w = p;
+ e = q + sz;
+ while (q < e) {
+ size_t n;
+
+ n = nul_length(q, e - q);
+
+ /* If there are more than the specified run length of
+ * NUL bytes, or if this is the beginning or the end
+ * of the buffer, then seek instead of write */
+ if ((n > run_length) ||
+ (n > 0 && q == p) ||
+ (n > 0 && q + n >= e)) {
+ if (q > w) {
+ l = write(fd, w, q - w);
+ if (l < 0)
+ return -errno;
+ if (l != q -w)
+ return -EIO;
+ }
+
+ if (lseek(fd, n, SEEK_CUR) == (off_t) -1)
+ return -errno;
+
+ q += n;
+ w = q;
+ } else if (n > 0)
+ q += n;
+ else
+ q++;
+ }
+
+ if (q > w) {
+ l = write(fd, w, q - w);
+ if (l < 0)
+ return -errno;
+ if (l != q - w)
+ return -EIO;
+ }
+
+ return q - (const uint8_t*) p;
+}
+
+char* set_iovec_string_field(struct iovec *iovec, size_t *n_iovec, const char *field, const char *value) {
+ char *x;
+
+ x = strjoin(field, value);
+ if (x)
+ iovec[(*n_iovec)++] = IOVEC_MAKE_STRING(x);
+ return x;
+}
+
+char* set_iovec_string_field_free(struct iovec *iovec, size_t *n_iovec, const char *field, char *value) {
+ char *x;
+
+ x = set_iovec_string_field(iovec, n_iovec, field, value);
+ free(value);
+ return x;
+}
+
+struct iovec_wrapper *iovw_new(void) {
+ return malloc0(sizeof(struct iovec_wrapper));
+}
+
+void iovw_free_contents(struct iovec_wrapper *iovw, bool free_vectors) {
+ if (free_vectors)
+ for (size_t i = 0; i < iovw->count; i++)
+ free(iovw->iovec[i].iov_base);
+
+ iovw->iovec = mfree(iovw->iovec);
+ iovw->count = 0;
+}
+
+struct iovec_wrapper *iovw_free_free(struct iovec_wrapper *iovw) {
+ iovw_free_contents(iovw, true);
+
+ return mfree(iovw);
+}
+
+struct iovec_wrapper *iovw_free(struct iovec_wrapper *iovw) {
+ iovw_free_contents(iovw, false);
+
+ return mfree(iovw);
+}
+
+int iovw_put(struct iovec_wrapper *iovw, void *data, size_t len) {
+ if (iovw->count >= IOV_MAX)
+ return -E2BIG;
+
+ if (!GREEDY_REALLOC(iovw->iovec, iovw->count + 1))
+ return -ENOMEM;
+
+ iovw->iovec[iovw->count++] = IOVEC_MAKE(data, len);
+ return 0;
+}
+
+int iovw_put_string_field(struct iovec_wrapper *iovw, const char *field, const char *value) {
+ _cleanup_free_ char *x = NULL;
+ int r;
+
+ x = strjoin(field, value);
+ if (!x)
+ return -ENOMEM;
+
+ r = iovw_put(iovw, x, strlen(x));
+ if (r >= 0)
+ TAKE_PTR(x);
+
+ return r;
+}
+
+int iovw_put_string_field_free(struct iovec_wrapper *iovw, const char *field, char *value) {
+ _cleanup_free_ _unused_ char *free_ptr = value;
+
+ return iovw_put_string_field(iovw, field, value);
+}
+
+void iovw_rebase(struct iovec_wrapper *iovw, char *old, char *new) {
+ for (size_t i = 0; i < iovw->count; i++)
+ iovw->iovec[i].iov_base = (char *)iovw->iovec[i].iov_base - old + new;
+}
+
+size_t iovw_size(struct iovec_wrapper *iovw) {
+ size_t n = 0;
+
+ for (size_t i = 0; i < iovw->count; i++)
+ n += iovw->iovec[i].iov_len;
+
+ return n;
+}
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